Widgets to-do

Here is a partial "To do" for the widget audit.  Don't consider it
comprehensive, but it covers most of it.

Coming imminently:

pulldown
- rename to combo (short version of combobox as used by swing - JComboBox)
- factor out of single xwt in monopoly (rod - in progress)

selectable
- add multi-select (me)

splitpane/splitbar:
- complete rewrite (me - in progress)

tab/tabpane
- complete rewrite (me - in progress)
- integrate with selectable / focusable (me)

table
- complete rewrite (me)
- factor layout into grid/column/row (me)

tree
- integrate with focusable selectable (rod)



Unassigned:

menu/menuitem
- complete rewrite
- names / namespace?

spin
- add date / list options
- monopoly not yet polished

slider
- audit

text
- label
- text
--- password ?
- textarea